&nbsp056 &nbspFXUS04 KWBC 050933 &nbspQPFPFD &nbsp &nbspQUANTITATIVE PRECIPITATION FORECAST DISCUSSION &nbspNWS WEATHER PREDICTION CENTER COLLEGE PARK MD &nbsp532 AM EDT TUE JUN 05 2018 &nbsp &nbspFINAL DAY 1, DAY 2 AND DAY 3 QPF DISCUSSION &nbspVALID JUN 05/1200 UTC THRU JUN 08/1200 UTC &nbspREFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR &nbsp &nbspDAY 1 &nbsp&nbsp &nbsp..NORTHERN PLAINS - UPPER MISSISSIPPI VALLEY &nbsp &nbspUPPER RIDGE AXIS PUSHES EAST OF THE NORTHERN PLAINS AND UPPER MS &nbspVALLEY REGION TUE NIGHT. IN ITS WAKE, AN UPTICK IN BROAD SCALE &nbspUPPER FORCING (DIVERGENCE ALOFT) WILL ENSUE, AND GET A &nbspCONSIDERABLE BOOST WITHIN THE RIGHT ENTRANCE REGION OF AN UPPER &nbspLEVEL JET STREAK TRAVERSING SOUTHERN ONTARIO. MEANWHILE, THE &nbspINCREASING (AND VEERING) NOCTURNAL LLJ WILL LEAD TO RAPID &nbspLOW-LEVEL MOISTURE/THETA E TRANSPORT AHEAD OF A SHARPENING FRONTAL &nbspZONE. BOTH SYNOPTIC AND THERMODYNAMIC INDICATORS GIVE CREDENCE TO &nbspTHE THE MULTI-MODEL SIGNAL OF A DEVELOPING MCS OVERNIGHT ALONG THE &nbsp"RING OF FIRE", THOUGH AS IS TYPICAL, THE MODEL SOLUTIONS ARE NOT &nbspWELL CLUSTERED WITH RESPECT TO THE DETAILS IN TERMS OF MCS TRACK &nbspAND THUS AXIS OF HEAVIEST RAINFALL. WPC DID NUDGE THE QPF AXIS A &nbspLITTLE FATHER SOUTH FROM THE PREVIOUS FORECAST -- ESSENTIALLY IN &nbspLINE WITH THE BLEND OF THE WRF-ARW, ARW2, AND NSSL-WRF (ALL OF &nbspWHICH ALIGNED REASONABLY WELL, WHILE THE NAM CONUS NEST, WRF-NMMB, &nbspNBM, AND GLOBAL GUIDANCE WERE FARTHER NORTH. DESPITE THE FAIRLY &nbspVIGOROUS MID-LEVEL CAP, BASED ON CLIMO LIKE THE AFOREMENTIONED &nbspHIGH-RES DEPICTION OF THE HEAVY RAINFALL FOOTPRINT FARTHER SOUTH, &nbspALONG AND NORTH OF THE SURFACE BOUNDARY WHERE THE COUPLING OF &nbspROBUST DEEP-LAYER ELEVATED INSTABILITY AND MOISTURE TRANSPORT WILL &nbspBE MAXIMIZED NORTH-NORTHEAST OF THE 700 MB +12C ISOTHERM. ALSO &nbspSUPPORTING A MORE SOUTHERN SOLUTION OF THE MCS TRACK/HEAVIEST QPF &nbspWOULD BE THE DEGREE OF SOUTHWARD PROPAGATION OVERNIGHT, AS THE &nbspS=SW LLJ BEGINS TO EXCEED THE SPEED OF THE MEAN 850-300 MB FLOW. &nbspAT THIS POINT, THE PROGGED SHEAR PROFILES WOULD SUPPORT A &nbspPROGRESSIVE MCS; HOWEVER, MULTIPLE ROUNDS OF CONVECTION AS NOTED &nbspFROM THE ARW/ARW2 (FIRST ONE ALONG THE INITIAL WNW-ESE WARM &nbspFRONTAL BOUNDARY) COULD POSE A MORE ENHANCED FLASH FLOOD RISK &nbspACROSS FAR NORTHEAST SD AND SOUTHEAST ND. &nbsp &nbsp&nbsp &nbsp..CENTRAL GULF COAST REGION &nbsp &nbspMID-UPPER SHORTWAVE TROUGH -- BOLSTERED EARLY IN THE PERIOD THE &nbspMCV OVER THE ARKLATEX -- WILL BE THE CATALYST FOR ADDITIONAL &nbspDIURNALLY-ENHANCED CONVECTION ALONG THE SURFACE STATIONARY FRONT &nbspSOUTH TOWARD THE GULF COAST. 0-6KM BULK SHEAR VALUES AOA 25 KTS &nbspALONG WITH ROBUST DEEP-LAYER INSTABILITY (MUCAPES AT 2000-3000+ &nbspJ/KG) WILL SUPPORT MORE ORGANIZED, WIDESPREAD COVERAGE DURING THE &nbspAFTERNOON THROUGH MID EVENING AHEAD OF THE UPPER TROUGH, WITH THE &nbspSURFACE MOISTURE CONVERGENCE GETTING AN ADDED BOOST FROM THE &nbspDEVELOPING GULF BREEZES. DESPITE THE RELATIVELY HIGH 1-3 HOURLY &nbspFFG (GENERALLY 2.5-3.0" IN 1 HOUR AND 3-4" IN 3 HOURS), LOCALIZED &nbspTOTALS OF 3-5" WITHIN A FEW HOURS PER THE HIGH-RES CAMS WOULD &nbspSUPPORT A MARGINAL RISK OF EXCESSIVE RAINFALL, PARTICULARLY OVER &nbspPORTIONS OF SE LA GIVEN THE RELATIVELY WETTER ANTECEDENT SOILS &nbsp(LOWER FFG VALUES). &nbsp &nbspHURLEY &nbsp &nbspDAY 2 &nbsp &nbsp...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL OVER THE CENTRAL &nbspPLAINS... &nbsp&nbsp &nbsp..NORTHERN ROCKIES TO CENTRAL PLAINS &nbsp &nbspWEAK SHORTWAVE ENERGY ROUNDING A BROAD MID-UPPER LEVEL RIDGE AXIS &nbspEXTENDING UP THE HIGH PLAINS WILL CROSS THE NORTH-CENTRAL GREAT &nbspPLAINS WEDNESDAY. A LOW LEVEL JET UNDER THE RIDGE WILL BRING GULF &nbspMOISTURE NORTH WITH 1.5 INCH PW OVER NE/IA WHICH IS TWO STANDARD &nbspDEVIATIONS ABOVE NORMAL. THE COMBINATION OF HIGH MOISTURE, &nbspINSTABILITY, AND MID LEVEL FORCING SHOULD BE ENOUGH TO BREAK THE &nbspCAP AND TRIGGER SCATTERED HEAVY THUNDERSTORMS THAT WILL SHIFT &nbspSOUTHEAST IN THE ANTICYCLONIC FLOW. MCS DEVELOPMENT IS LIKELY &nbspGIVEN THE STRONG INSTABILITY AND EXPECTED FORWARD PROPAGATION. &nbsp &nbspQPF WAS BASED ON A BLEND OF THE 00Z GFS/NAM/ECMWF AND IN-HOUSE &nbspBIAS-CORRECTED BLEND. THE MARGINAL RISK IS FOR THE MAIN CONVECTIVE &nbspSTORM BREEDING GROUND EAST OF THE SAND HILLS WHERE 6-HR FFG IS &nbspGENERALLY 2 TO 2.5 INCHES. PROGRESSION OF ORGANIZED/MCS ACTIVITY &nbspMAY NEED TO BE ACCOUNTED FOR IN SUBSEQUENT QPF AND ERO. &nbsp &nbsp&nbsp &nbsp..FLORIDA &nbsp &nbspA SWATH OF 1.75 INCH PW ALONG A STALLED FRONT WILL ALLOW HEAVY &nbspRAIN ACROSS CENTRAL FL. LIGHT EASTERLY MEAN FLOW COULD ALLOW &nbspREPEATING CELLS OFF THE GULF. FFG IS QUITE HIGH IN CENTRAL FL, SO &nbspFLASH FLOODING IS LIKELY LIMITED LOCALLY. &nbsp &nbspDAY 3 &nbsp &nbsp...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL OVER THE CENTRAL &nbspPLAINS AND NORTHERN HIGH PLAINS... &nbsp&nbsp &nbsp..NORTHERN ROCKIES TO CENTRAL PLAINS &nbsp &nbspWEAK SHORTWAVE ENERGY ROUNDING A BROAD MID-UPPER LEVEL RIDGE AXIS &nbspEXTENDING UP THE HIGH PLAINS WILL CROSS THE NORTHERN GREAT PLAINS &nbspTHURSDAY. A WAKE FROM WEDNESDAY ACTIVITY SHOULD EXIST OVER THE &nbspNORTH-CENTRAL PLAINS THURSDAY WITH DEVELOPMENT LIKELY INITIATION &nbspALONG REMNANT BOUNDARIES. 1.25 TO 1.5 INCH PW IS 1.5 TO 2 STANDARD &nbspDEVIATIONS ABOVE NORMAL. INSTABILITY IS PROGGED TO BE STRONGER &nbspOVER THE CENTRAL PLAINS THEN MT WHICH MAY ALLOW FOR GREATER MCS &nbspDEVELOPMENT. MORE DETAILS ON MESOSCALE PROCESSES ON SUBSEQUENT &nbspFORECASTS. &nbsp &nbspQPF WAS BASED ON A BLEND OF THE 00Z GFS/NAM/ECMWF AND IN-HOUSE &nbspBIAS-CORRECTED BLEND. THE MARGINAL RISKS OVER MT AND NE/KS/IA IS &nbspBASED ON 00Z CONSENSUS FOR THE LOW POSITION ALONG WITH MORE &nbspSENSITIVE FFG. &nbsp &nbspHURLEY/JACKSON &nbsp &nbspGRAPHICS AVAILABLE AT WWW.WPC.NCEP.NOAA.GOV/QPF/QPF2.SHTML &nbsp &nbsp &nbsp